SQLServerCentral.com / SQL Server 2008 / T-SQL (SS2K8) / Do you really need the log file / Latest PostsInstantForum.NET v2.9.0SQLServerCentral.comhttp://www.sqlservercentral.com/Forums/notifications@sqlservercentral.comSun, 02 Aug 2015 19:00:42 GMT20RE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspx[quote][b]mike 57299 (2/6/2013)[/b][hr]A full backup doesn't set the log to re-usable?[/quote]No.Please read through this - [url=http://www.sqlservercentral.com/articles/64582/]Managing Transaction Logs[/url]Wed, 06 Feb 2013 09:24:32 GMTGilaMonsterRE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxA full backup doesn't set the log to re-usable?Wed, 06 Feb 2013 09:10:39 GMTmike 57299RE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxBetween 6pm and 7am you dont do transaction log backups, during that time the log cannot be marked as re-usable so that is why you have a huge transaction log as you have 13 hours worth of transactions waiting to be backed up.Do your transaction logs every hour on the hour all day, not just during the working day.Wed, 06 Feb 2013 08:06:16 GMTanthony.greenRE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxWe do hourly transaction log backups during the work day.MikeWed, 06 Feb 2013 07:59:23 GMTmike 57299RE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxYou can't switch to simple recovery with active database mirroring. You'll need to completely drop the database mirroring setup, then you can change recovery models. Recreating the mirror will require copying over and restoring a full or diff backup. That's a fair bit of work and you'll be completely without the mirror while that's done.[quote]We do daily backups at 11pm, a diff backup at 6am and hourly transaction logs from 7 am - 6 pm - plus the mirroring.[/quote]That's probably part of the cause of the large log, the lack of log backups for 13 hours a day. I suggest log backups on the hour, every hour.Wed, 06 Feb 2013 00:31:28 GMTGilaMonsterRE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxWe are running out of space on our mirror server. I though that if I could reduce the log, it would give us some breathing room while we figure out a solution.We do daily backups at 11pm, a diff backup at 6am and hourly transaction logs from 7 am - 6 pm - plus the mirroring.I don't think the shrink would work. It hasn't in the past when I restore a backup to my local machine.MikeTue, 05 Feb 2013 23:41:33 GMTmike 57299RE: Do you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxOne, the ability to do point in time recovery of the database if it is needed. Having a mirror database is good for high availability but it doesn't replace the need for a good set of backups from which to recover if necessary.Second, breaking and re-establishing the mirror is not really the best thing you can do.Why do you want to truncate the log, or is shrinking the log what you are actually talking about. They are two entirely different things.Tue, 05 Feb 2013 23:30:06 GMTLynn PettisDo you really need the log filehttp://www.sqlservercentral.com/Forums/Topic1416238-392-1.aspxWe have a 70 GB mdf w/ a 29GB ldf. After doing full backup, can I truncate the log via the following plan:&lt;Break mirroring&gt;alter database xxx set recovery simple&lt; right click - properties - files - set size to 5GB &gt;alter database xxx set recovery full&lt;Reset mirroring&gt;What do I lose by truncating the log after a full backup?Thanks,MikeTue, 05 Feb 2013 22:28:10 GMTmike 57299